There has hitherto been proposed a variety of mechanisms for feeding a photographic film housed in a cassette and having a single perforation in each frame. In most film feeding mechanisms, a detection pawl is maintained resiliently urged even by a small force against the circumferential wall of the perforation from the time when the film is stopped by the detection pawl until the operation of the shutter is completed, thus incurring a risk of a film being inadvertently shifted due to vibrations or the like.